Romney’s strong debate performances last week, in which he pounded on the former House speaker over his tumultuous speakership and consulting work for mortgage giant Freddie Mac, proved to be crucial. According to early exit polls, about two-thirds of Florida primary voters cited the debates as important in how they voted.

Florida, the fourth largest state in the country, is by far the biggest prize to date, with 50 GOP convention delegates at stake. In some ways, Florida is a microcosm of the country, with large minority populations and residents who have moved here from all over the United States. Romney’s victory portends an ability to play to varied crowds in future primaries.

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The exit polls show about 45 percent of Florida GOP voters said that the ability to defeat President Obama was the most important quality in a candidate. The top issue was the economy, selected by 60 percent of voters.

Despite Romney’s resounding victory in Florida, the three other candidates in the race all say they’ll continue to compete.

On Tuesday, before the polls closed, Gingrich promised to remain in the race “probably six months – [until] probably June or July – unless Mitt Romney drops out earlier.”

Mr. Santorum, a former senator from Pennsylvania and winner of the Iowa caucuses, has a strong following among social conservatives.

Congressman Paul from Texas is well-funded and has a devoted following among young voters and libertarians.

Paul did not campaign in Florida, focusing instead on the next contests in Maine, Nevada, and Colorado. Santorum left Florida early, and missed some days of campaigning when his young disabled daughter fell seriously ill. After her situation stabilized, Santorum resumed his campaign in Colorado and Nevada.

The biggest lesson of Florida may be that money and organization really do matter in a large state. Before the Florida primary, a candidate with time to go county by county and shake a lot of hands could do well; that’s how Santorum won the Iowa caucuses. In the Sunshine State, that’s not enough.

Given Florida’s 19 million people and 10 media markets, Romney was the only candidate with the resources and staff to compete comfortably statewide. Gingrich also had the support of a well-funded super political-action committee, which aired ads in the state. But that wasn’t enough to help the former speaker overcome Romney’s attacks in the debates and on the airwaves.

Indeed, Romney likely owes his victory in Florida more than anything to the two debates here. Romney encountered some bumps last week when he released his tax returns, revealing a low effective tax rate, accounts in the Cayman Islands and Switzerland (on which he paid US taxes), and significant donations to the Mormon church.

But the fact that Romney is extremely wealthy was not news, and for now, nothing untoward in his finances has emerged.